/**
 * Copyright (C) 2010-2013 Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.rocketmq.client.impl.consumer;

import java.util.List;
import java.util.Set;

import com.alibaba.rocketmq.client.consumer.AllocateMessageQueueStrategy;
import com.alibaba.rocketmq.client.consumer.MessageQueueListener;
import com.alibaba.rocketmq.client.impl.factory.MQClientInstance;
import com.alibaba.rocketmq.common.message.MessageQueue;
import com.alibaba.rocketmq.common.protocol.heartbeat.ConsumeType;
import com.alibaba.rocketmq.common.protocol.heartbeat.MessageModel;

/**
 * @author shijia.wxr<vintage.wang@gmail.com>
 * @since 2013-6-22
 */
public class RebalancePullImpl extends RebalanceImpl {
	private final DefaultMQPullConsumerImpl defaultMQPullConsumerImpl;

	public RebalancePullImpl(DefaultMQPullConsumerImpl defaultMQPullConsumerImpl) {
		this(null, null, null, null, defaultMQPullConsumerImpl);
	}

	public RebalancePullImpl(String consumerGroup, MessageModel messageModel, AllocateMessageQueueStrategy allocateMessageQueueStrategy, MQClientInstance mQClientFactory, DefaultMQPullConsumerImpl defaultMQPullConsumerImpl) {
		super(consumerGroup, messageModel, allocateMessageQueueStrategy, mQClientFactory);
		this.defaultMQPullConsumerImpl = defaultMQPullConsumerImpl;
	}

	@Override
	public long computePullFromWhere(MessageQueue mq) {
		return 0;
	}

	@Override
	public void dispatchPullRequest(List<PullRequest> pullRequestList) {
	}

	@Override
	public void messageQueueChanged(String topic, Set<MessageQueue> mqAll, Set<MessageQueue> mqDivided) {
		// 7.1） 获取DefaultMQPullConsumer.messageQueueListener变量的值，该变量只有在应用层使用MQPullConsumerScheduleService类来进行计划拉取消息服务时才会设置MessageQueueListener对象；
		// 该对象是MQPullConsumerScheduleService类的内部类MessageQueueListenerImpl类的实例；
		MessageQueueListener messageQueueListener = this.defaultMQPullConsumerImpl.getDefaultMQPullConsumer().getMessageQueueListener();
		if (messageQueueListener != null) {
			try {
				// 7.2）调用该内部类的实例MessageQueueListener对象的messageQueueChanged方法；
				messageQueueListener.messageQueueChanged(topic, mqAll, mqDivided);
			} catch (Throwable e) {
				log.error("messageQueueChanged exception", e);
			}
		}
	}

	@Override
	public boolean removeUnnecessaryMessageQueue(MessageQueue mq, ProcessQueue pq) {
		this.defaultMQPullConsumerImpl.getOffsetStore().persist(mq);
		this.defaultMQPullConsumerImpl.getOffsetStore().removeOffset(mq);
		return true;
	}

	@Override
	public ConsumeType consumeType() {
		return ConsumeType.CONSUME_ACTIVELY;
	}
}
